Investigators from the Cardiovascular Health Study Coordinating Center at the University of Washington propose to establish a Coordinating Center (CC) which will participate with the Field Centers and the National Heart, Lung, and Blood Institute (NHLBI) in conducting a study of the cardiovascular consequences of sleep apnea and other sleep-related breathing disorders (SRBD). The CC will subcontract with Case Western Reserve University to provide expertise in the study of sleep disorders and to establish a Sleep Reading Center for the central processing of all data on sleep apnea and other SRBD. The primary objective of the study is to determine the degree to which SRBD are risk factors for the development of cardiovascular and cerebrovascular disease, as well as to examine possible associations with other cardiovascular risk factors. We will also investigate the degree to which SRBD affect prognosis in individuals with sub-clinical or clinical cardiovascular disease. The study will use existing, well-characterized population-based cohorts as participants in this study. The Coordinating Center will provide biostatistical expertise, data management, reporting services, data analysis, and overall study coordination and management. The Coordinating Center will collate and analyze data collected in parent studies for comparability across studies, and will collect, edit, store, and analyze data generated by the Field Centers for the study of SRBD. The Coordinating Center investigators will collaborate with other investigators in analyzing the study data for presentation and publication.